Drive a Zafira 1.6? Get 7 more mpg!

No, cos thats not what I said. At WOT you are injecting more fuel but if 33% of that energy is turned to motived power rather than 20% at light cruise with narrow throttle, then yes DAMN RIGHT ITS MORE EFFICIENT. But you end up with a massive excess of power than what you need to do 70-80. Maybe I meant higher throttle angles rather than full WOT as full throttle will start to shift your fuel ratios around.

Look at an isobar graph of engine BSFC if you want to start thinking beyond what you think is right.
 
Not that I can get my head around the nuances of this argument, but as an interesting aside, I remember the M3 Vs Prius Topgear segment, on the same amount of fuel, the M3 got significantly further around the track (clearly lots of WOT), showing much more efficiency under those hard conditions, yet at a constant 56MPH, the Prius would clearly go further then the M3 on the same fuel..
 
Jonnycoupe said:
This is the UK, there is no such thing as 'crap' fuel.

Are you suggesting normally unleaded has to be significantly richer than stoich just to maintain cruise and the gains of Super is from running stoichiometric mixture? No didnt think so.
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95ron is crap and pinks in high compression engines. the 99ron stuff is much much better.

this is what my ecu does set to 95ron:
2 = Idle speed increase by 100rpm.
3 = +5% fuel acceleration enrichment.
4 = +5% fuel enrichment throughout range.
5 = Ignition retarded by 5deg throughout rev/load range.

when set to 98 ron it does none of that, thus mpg goes up as it should do.
 
Jonnycoupe said:
No, cos thats not what I said. At WOT you are injecting more fuel but if 33% of that energy is turned to motived power rather than 20% at light cruise with narrow throttle, then yes DAMN RIGHT ITS MORE EFFICIENT. But you end up with a massive excess of power than what you need to do 70-80. Maybe I meant higher throttle angles rather than full WOT as full throttle will start to shift your fuel ratios around.

Look at an isobar graph of engine BSFC if you want to start thinking beyond what you think is right.
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Right, so it isn't more efficient in terms of fuel used and distance travelled (ie. MPG, like we're discussing). I'm not ashamed to say that you are getting into areas that are way above my head, but real world experience tells me that both gains with SUL are possible, as is getting the same fuel economy from a 1.2 and a 2.0 Turbo, especially on faster routes.

Disco Boy said:
It's pointless debating with someone who genuinely thinks that that is a scientifically rigorous and accurate test...
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Who has claimed that?
 
It's aimed at everyday driving making stupid points like 'if I thrash the **** out of a slow car it uses more fuel than a fast car driven normally' totally stupid.
 
MikeHiow said:
Right, so it isn't more efficient in terms of fuel used and distance travelled (ie. MPG, like we're discussing). I'm not ashamed to say that you are getting into areas that are way above my head, but real world experience tells me that both gains with SUL are possible
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It's great having Jonny here as he can put some real science and knowledge behind this, but yet you are still going on about 'Well my real world experience says this so this is what is happening' whilst ignoring/not understanding the physcis behind it. This isn;t far off from being similar to the discussion of Hi-fi cabling :p

More from you please Jonny :D
 
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No, you have it the wrong way around.

It's more like, If I drive a slow car and a fast car at the same speeds....

-Ad- said:
It's great having Jonny here as he can put some real science and knowledge behind this, but yet you are still going on about 'Well my real world experience says this so this is what is happening' whilst ignoring/not understanding the physcis behind it.

More from you please Jonny :D
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What use are the physics behind it (told to me by some random person on an internet forum) when my own experience, and the experience of many others completely contradict what he is trying to tell me.
 
[TW]Fox;17226656 said:
It's aimed at everyday driving making stupid points like 'if I thrash the **** out of a slow car it uses more fuel than a fast car driven normally' totally stupid.
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Is that aimed at me? It's hard to keep up with a thread with so many crossed opinions..
 
Demon said:
Not that I can get my head around the nuances of this argument, but as an interesting aside, I remember the M3 Vs Prius Topgear segment, on the same amount of fuel, the M3 got significantly further around the track (clearly lots of WOT), showing much more efficiency under those hard conditions, yet at a constant 56MPH, the Prius would clearly go further then the M3 on the same fuel..
Click to expand...

Under those conditions the Prius is actually charging the batteries aswell so it ended up with a storage of electricity it could do some range on and would have changed the MPG massively.
 
MikeHiow said:
What use are the physics behind it (told to me by some random person on an internet forum) when my own experience, and the experience of many others completely contradict what he is trying to tell me.
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You seem to be declaring that your experience is controlled test data?

You cant really compare engines when they are in different chassis's either. Aerodynamics etc will play a big difference. Look at a 1.8 Focus Mk1. The Estate and Saloon are significantly more aerodynamic.
 
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